# PyScheme lambda language written in Python
#
# Expressions (created by the parser) for evaluation
#
# Copyright (C) 2018  Bill Hails
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

stack = []

def trace(method):
    def wrapper(*args, **kwargs):
        global stack
        stack += [args[0]]
        ret = method(*args, **kwargs)
        stack.pop()
        return ret
    return wrapper
